The present invention relates to a lather and, more particularly, to a lathe with automatic cross feeding and retraction functions.
A conventional lathe includes a sliding track mounted on a lathe body. A cutter base can translate along the sliding track. A cross sliding seat is mounted on the cutter base and is threadedly coupled to a transverse hand wheel with a screw rod. A user can rotate the transverse hand wheel to slide the cross sliding seat on the cutter base. A cutter fixing seat is mounted on the cross sliding seat for fixing a cutter. The cutter base further includes an operation table mounted on a side of lathe body. A rack is mounted parallel to and beside the sliding track. A translation hand wheel is mounted on the operation table and meshes with the rack. A guiding screw is mounted on the side of the lathe body. A half-nuts seat is mounted in the operation table and can be controlled by a thread cutting handle to provide a clutch function with the guiding screw. Furthermore, a thread cutting indicator is mounted to a side of the operation table and is connected to the guiding screw. A dial is provided on the thread cutting indicator to indicate the thread rotational angle. A micro switch is provided to a bottom of the operation table. A guiding rod is mounted to the side of the lathe body. At least one limiting ring is provided on the guiding rod to cooperate with the micro switch that can be set to define the start point and the end point of movement of the cutter base.
During thread cutting, a workpiece is fixed to a fixing mechanism on a driving shaft, and a cutter is fixed on the cutter fixing seat. The transverse hand wheel is rotated to slide the cross sliding seat on the cutter seat. The dial on the transverse hand wheel permits the user to record and adjust the amount of feeding. Furthermore, the thread cutting indicator indicates the scale of the thread rotational angle. The thread cutting handle is moved to engage the half-nuts seat with the guiding screw. The guiding screw is rotated to move the cutter seat and the cutter towards the workpiece, thereby proceeding with thread cutting on the workpiece.
When the cutter seat moves to a position in which the micro switch contacts with the limiting ring, the lathe automatically stops the processing movement. The user has to manually rotate the transverse hand wheel to move the cutter outwards for retraction purposes. Then, the translation hand wheel is manually rotated or driven by a motor to translate the cutter seat to the start point of processing. Next, the transverse hand wheel is rotated back to correspond to the angular position of the dial in the first processing, and the feed amount is increased. The above procedures are repeated several times to accomplish the thread cutting step by step.
However, to prevent failure of the thread cutting, the scale of the thread cutting indicator must be the same every time the half-nuts seat engages with the guiding screw. Manual operation is generally required in the operation of the above lathe, particularly in the thread cutting process, repeated manual procedures, including adjusting the feed amount, switching the thread cutting handle and the half-nuts seat to engage with or disengage from the guiding screw, manually retracting the cutter, etc., are carried out. Furthermore, the feed amount has to be recorded every time during processing to avoid excessive adjustment that could damage the cutter or the workpiece. Furthermore, during feeding of the cutter, the user must notice whether the angular position of the dial of the thread cutting indicator is the same. The whole processing process is troublesome and complicated.
Thus, a need exists for a novel lathe with automatic cross feeding and retraction functions to mitigate and/or obviate the above drawbacks.